While various orally disintegrating tablets and production methods thereof are heretofore known, achievement of good disintegrability and tablet strength is difficult since the both properties are conflicting. In recent years, moreover, the desired level of tablet strength has become high, since the tablet should not break during production and distribution processes, as well as stand the packaging by automatic packaging machines in pharmacy and the like. Particularly, a tablet which is rapidly-disintegrated in an oral cavity having a high content of an active ingredient faces difficulty in affording both superior rapid-disintegrability in an oral cavity and superior tablet strength, since it can contain only reduced amounts of excipient, disintegrant and the like to be added besides an active ingredient, which contribute to the good rapid-disintegrability and sufficient strength, so as to produce a tablet with an easily ingestible size.
As a tablet which is rapidly disintegrated in an oral cavity having a high active ingredient content percentage, a tablet containing droxidopa as an active ingredient, and mannitol and cornstarch is known (see patent document 1). In addition, a tablet which is rapidly disintegrated in an oral cavity containing polaprezinc as an active ingredient, and mannitol, hydroxypropylstarch and crospovidone (trade name: Promac D tablets 75) has been reported. However, a tablet superior in both the rapid-disintegrability in an oral cavity and tablet strength, as well as a production method thereof have been further desired.    [patent document 1] WO 06/123678    [patent document 2] WO 00/047233